"I know why the caged birds sing" of Maya Angelou

I Know Why the Caged Bird Sings is the 1969 autobiography about the early years of African-American writer and poet Maya Angelou. The first in a seven-volume series, it is a coming-of-age story that illustrates how strength of character and a love of literature can help overcomeracism and trauma. The book begins when three-year-old Maya and her older brother are sent to Stamps, Arkansas, to live with their grandmother and ends when Maya becomes a mother at the age of 17. In the course of Caged Bird, Maya transforms from a victim of racism with an inferiority complex into a self-possessed, dignified young woman capable of responding to prejudice.
I know why the caged bird sings, ah me,
When his wing is bruised and his bosom sore,
When he beats his bars and would be free;
It is not a carol of joy or glee,
But a prayer that he sends from his heart's deep core,
But a plea, that upward to Heaven he flings –
I know why the caged bird sings